package Games::Go::Coordinate;

use warnings;
use strict;


our $VERSION = '0.03';


use base qw(Class::Accessor::Complex);


use overload
    '""'  => 'stringify',
    'cmp' => 'str_cmp';


__PACKAGE__
    ->mk_new
    ->mk_accessors(qw(x y));


# accept something like 'ac' and set x=1, y=3
sub set_sgf_coordinate {
    my ($self, $coord) = @_;
    my ($x, $y) = map { ord($_)-96 } split // => lc($coord);
    $self->x($x);
    $self->y($y);
}


sub new_from_sgf_coordinate {
    my ($class, $coord) = @_;
    my $self = $class->new;
    $self->set_sgf_coordinate($coord);
    $self;
}


sub to_sgf {
    my $self = shift;
    join '' => map { chr($_+96) } $self->x, $self->y;
}


sub as_list {
    my $self = shift;
    sprintf '(%d,%d)', $self->x, $self->y;
}


sub stringify {
    my $self = shift;
    $self->to_sgf;
}


sub str_cmp {
    my ($lhs, $rhs, $reversed) = @_;
    $_ = "$_" for $lhs, $rhs;
    ($lhs, $rhs) = ($rhs, $lhs) if $reversed;
    $lhs cmp $rhs;
}


sub translate {
    my ($self, $dx, $dy) = @_;
    $self->x($self->x + $dx);
    $self->y($self->y + $dy);
}


1;


__END__

{% USE p = PodGenerated %}

=head1 NAME

Games::Go::Coordinate - represents a board coordinate in the game of Go

=head1 SYNOPSIS

    use Games::Go::Coordinate;

    my $c1 = Games::Go::Coordinate->new(x => 4, y => 3);
    my $c2 = Games::Go::Coordinate->new(x => 4, y => 10);
    if ($c2 gt $c1) { ... }

=head1 DESCRIPTION

This class represents a board coordinate in the game of Go. Coordinate objects
can be compared (as strings) to see whether two ranks are equal or whether one
rank is higher than the other. Coordinate objects stringify to the SGF
notation (for example, C<(4,10)> stringifies to C<dj>.

{% p.write_inheritance %}

=head1 METHODS

=over 4

{% p.write_methods %}

=item set_sgf_coordinate

    $coord->set_sgf_coordinate('cf');

Takes a coordinate in SGF notation and sets C<x()> and C<y()> from it.

=item new_from_sgf_coordinate

    my $cord = Games::Go::Coordinate->new_from_sgf_coordinate('cf');

Alternative constructor that accepts an SGF coordinate and sets C<x()> and
C<y()> from it.

=item to_sgf

Returns the coordinate in SGF notation. This is also how the coordinate object
stringifies.

=item as_list

Returns the coordinate in C<(x,y)> notation. For example, it might return a
string C<(16,17)>.

=item translate

    $coord->translate(2, -3);

Takes as arguments - in that order - a horizontal delta and a vertical delta
and translates the coordinate by those deltas.

=back

{% PROCESS standard_pod %}

=cut

